Anterior Segment Parameters of Filipino-Americans Compared to Chinese-Americans and Caucasian Americans Using Anterior Segment Optical Coherence Tomography

PURPOSE: We compare anterior segment characteristics of Filipino- versus Chinese- and Caucasian-Americans to describe the differences in risk factors among each ethnic group. METHODS: A cross-sectional study was conducted among Filipino, Chinese, and Caucasian subjects without glaucoma who underwent a standardized set of ocular examinations and anterior segment optical coherence tomography (Visante ASOCT) imaging. Zhongshan Angle Assessment Program (ZAAP) 4 was used for ASOCT image analysis. The following quantitative parameters wereobtained from ZAAP: (1) angle opening distance (AOD500, AOD750), angle recess area at 750 μm (ARA), and trabecular-iris space area at 500 and 750 μm (TISA500, TISA750); (2) iris parameters, including iris thickness at 750 μm from the scleral spur (IT750), iris area (IArea), iris curvature or convexity (ICurv), and pupil diameter; 3) anterior chamber parameters; and (4) lens vault. RESULTS: The Filipino (122 eyes), Chinese (121 eyes), and Caucasian (111 eyes) subject groups were similar in terms of demographic and clinical characteristics. We reported pairwise comparisons of Filipino parameter values to Chinese or Caucasian values, represented as B-coefficients and P values. In multivariate analysis, Filipinos had narrower angles than Caucasians (AOD750, TISA 500, TISA 750, ARA, P < 0.001). Filipinos had thicker and more convex irises than Caucasians (IT750, IT 2000, ICurv P < 0.003). Angle and iris parameters were similar overall for Filipino and Chinese. CONCLUSIONS: Filipinos appear to have more convex and thicker irises, smaller lens vault and narrower angles compared to Caucasians. Filipino eyes closely resembled Chinese eyes with similar iris and angle parameters. TRANSLATIONAL RELEVANCE: The anatomic angle parameters of Filipinos may contribute to angle closure risk among this population, thus ASOCT and thorough angle analysis is recommended in this population.